Merge branch 'sim-rat-exp' of https://github.com/petercollingridge/khan-exercises into petercollingridge-sim-rat-exp
Replace numeric degrees with symbolic label:

Due to rounding errors when converting to niceAngles,
the numeric value displayed can lead to invalid
triangles. i.e. an SSA triangle with side, side, angle
values that produces a triangle that does not exist.

This change is to just replace the numeric rounded value
displayed with a theta character to show that the angles
are equal and that the bisector theorem can be used.
Redo rational expression module
Merge remote-tracking branch 'upstream/master'
Add exercises to plurals
Use plural exercises in arith word problems
Make hints more consistent
Fix to use new randRangeUnique

randRangeUnique was return an index out of range

Test plan: run exercise a few times and make sure the question isn't undefined.

fix #45048 and many others

auditors chbl, eater
Merge pull request #45051 from petercollingridge/push-ups

Add exercises to plurals
Fix geometry_proofs_1 not showing problems

fix #45045; fix #45040; fix #45039; fix #45025; fix #45015; fix #44994;
fix #44986; fix #44983; fix #44965; fix #44964; fix #44938; fix #44916;
fix #44910; fix #44902; fix #44798; fix #44659

Test plan: Load geometry_proofs_1 locally, note javascript errors. Discovered this was happening when randRangeUnique was returning the upper bound, which it didn't use to do. After then change of decrementing the lower bound, exercise loaded fine locally.

Auditors: alpert
Re-run the exercises through the updated cleaner.
Skip try-catch in ?debug mode

Test Plan:
Saw an exception in the network panel!

Auditors: eater
Merge pull request #44904 from awmorgan/master

angle-bisector-theorem: replace numeric with symbolic angle
Add in some missing wpluralization words and fix an issue with cardinal() pluralizing when it should've been singular.
Brainfart, jumping jack already existed.
Fix issue with congruent_triangles_2 not showing x

fix #45164; fix #45163; fix #45162; fix #45155; fix #45143; fix #45142;
fix #45141; fix #45140; fix #45134; fix #45125; fix #45105; fix #45101;
fix #45098; fix #45094; fix #45087; fix #45082; fix #45076; fix #45065;
fix #45057; fix #45044; fix #45034; fix #44966; fix #44928; fix #44817;
fix #36534; fix #32123

Test plan: http://localhost:8000/exercises/congruent_triangles_2.html?seed=62&problem=parr&debug note that "x" is shown.
Fix the last place we're using %s in $._() messages.

Auditor: john

Test plan:
Fingers crossed
Oops, missed one place with %s in this file... :-(

Auditor: john
Merge branch 'master' of github.com:Khan/khan-exercises
Fix an issue where data-elses were being resolved twice, which was incorrect. Fixes #45253.